Many sports require protective headgear. American football, hockey, lacrosse, and baseball are sports that require headgear for at least certain activities that occur during a game.
American football has long required that a player wear a helmet. Most helmets today have a hard shell, a liner, a facemask, and a chinstrap for retaining the helmet on the head of the wearer.
For American football, various entities have promulgated standards to regulate the effectiveness helmets in protecting players. The National Operating Committee on Standards for Athletic Equipment (NOCSAE), for example, has issued the “Standard Performance Specification for Newly Manufactured Football Helmets, NOCSAE DOC (ND)002-98m05 (Modified July, 2005). Another standard is one issued by the American Society for Testing and Measurement (ASTM), ASTM F717-89(2006) Standard Specification for Football Helmets. These standards measure linear acceleration of a head form resulting from an impact.
Alternative and supplemental standards have been proposed. U.S. Pat. No. 6,871,525 proposes a method and apparatus for testing football helmets. The proposed method includes measurements of linear and rotation head acceleration due to impacts.
Despite the use of improved helmets and despite the existence of standards, however, significant numbers of football players still suffer concussions. It is estimated that over 100,000 football players suffer concussions each year.
One problem with football helmets is that they do not just serve as a means for protection for the wearer. They also serve as a striking instrument in high impact collisions between players. The National Football League, for example, has conducted studies of helmet-to-helmet collisions that caused a concussion. These studies indicate that a “concussion in professional football involves a mean impact velocity of 9.3 m/second (20.8 mph) and a head velocity change of 7.2 m/second (16.1 mph).” Pellman E J, Viano D C, Concussion in Professional Football: Summary of the Research Conducted by the National Football League's Committee on Mild Traumatic Brain Injury, Neurosurgery Focus. 2006; Vol. 21. Helmet-to-helmet impacts at such velocities can easily result in concussion.
Existing standards make no requirement that a striking player's helmet reduce the peak forces transmitted through the striking player's helmet during a collision. Instead, standards only focus on the helmet worn by the player being struck. Unfortunately, in an effort to make helmets better able to withstand impacts, the rigidity of the shell of the helmet is often increased. While a more rigid helmet may marginally better protection to the wearer, it also creates a helmet that is a more devastating instrument in causing concussions in helmet-to-helmet collisions.
The prior art suffers from certain shortcomings or limitations. The purpose of the present invention is to overcome the shortcomings or limitations in the prior art.